10 CYSTOSEIRA. 



fronds 1 — 4 feet long, alternately branched ; branches about a line wide, 

 pinnated with similar raniuli, and in the upper part with air-vessels and 

 receptacles. Air-veessels resembling pods or siliquae, whence the specific 

 name. The beautiful Fuctis osmundaceus, Turn. Hist. t. 105, is a second 

 species of this genus. 



III. Cystoseira. Ag. [Plate 1, B.] 



Frond much branched, occasionally leafy at base ; branches 

 becoming more slender upwards, and containing strings of 

 simple air-vessels within their substance. Receptacles ter- 

 minal, small, cellular, pierced by numerous pores, which 

 commimicate with immersed spherical conceptacles, con- 

 taining parietal spores and tufted antheridia. Name, KvaTig, 

 a bladder, and a-et^a, a chain ; because the air-vessels are 

 generally arranged in strings or series. 



1. C ericoides, Good. & Woodw. ; stem thick, woody, 

 short, cylindrical, beset with numerous, slender, filiform 

 branches, vai-iously divided, and densely clothed with small, 

 spine-like, awl-shaped ramuli (or leaves) ; air-vessels small, 

 solitary near the apices : receptacles cylindrical, terminal, 

 spiny. Grev. Alg. Brit. p. 4 ; Hook. Br. Fl. ii. p. 265 ; E. 

 Bot. t. 1968; Wyatt, Alg. Damn. No. 1 ; Harv. Phyc. Brit, 

 t. cclxv. 



Rocks between tide-marks, chiefly in the S. West of England and West 

 and South of Ireland ; common. Perennial. Summer and autumn. — 

 Root a large and very hard disk. Frond one or two feet long, remarkably 

 bushy, of a fine olive or yellowish green when removed from the water, but 

 appearing, whilst growing beneath the surface, to be clothed with the rich- 

 est iridescent tints. Air-vessels generally solitary, and immediately sub- 

 tending the terminal receptacles, very small ; sometimes scattered along 

 the branches. 



2. C. granulata, L. ; stem cylindrical, covered with ellip- 

 tical knobs, each of which bears a slender, repeatedly divided, 

 dichotomo-pinnated, cylindrical branch, irregularly set with 

 scattered, incurved, awl-shaped, spine-like ramuli ; air-ves- 

 sels small, linear-oblong, two or three together in the upper 

 part of the branches ; receptacles elongated. Grev. Alg. Brit, 

 p. 5,t.2; Hook. Brit. Fl ii. p. 265 ; E. Bot. /. 2169 ; Wyatt, 

 Alg. Damn. No. 101. Harv. Phyc. Brit. t. Ix. 



Rocky pools left by the tide on the coasts of England and Ireland, not 

 uncommon. Perennial. Summer. — i2oo< a flattish disk. >S'/f>H about 

 the thickness of a goose-quill, 7 or 8 inches high ; branches very slender, a 

 foot or more in length, very much divided, each having at its base a hard 

 bulbous hioh, which forms one of the most striking characters of the spe- 

 cies. Colour a semi-transparent olive-green. 



